Hearing devices are wearable hearing apparatus used to assist the hard-of-hearing. To meet the numerous individual requirements different designs of hearing device are provided such as behind-the ear (BTE) hearing devices, in-the-ear (ITE) hearing devices and Concha hearing devices. The typical configurations of hearing device are worn on the outer ear or in the auditory canal. Above and beyond these designs however there are also bone conduction hearing aids, implantable or vibro-tactile hearing aids available on the market. In such hearing aids the damaged hearing is simulated either mechanically or electrically.
Hearing devices principally have as their main components an input converter, an amplifier and an output converter. The input converter is as a rule a sound receiver, e.g. a microphone, and/or an electromagnetic receiver, e.g. an induction coil. The output converter is mostly implemented as an electroacoustic converter, e.g. a miniature loudspeaker or as an electromechanical converter, e.g. bone conduction earpiece. The amplifier is usually integrated into a signal processing unit. This basic structure is shown in FIG. 1 using a behind-the ear hearing device as an example. One or more microphones 2 for recording the sound from the surroundings are built into a hearing device housing 1 worn behind the ear. A signal processing unit 3, which is also integrated into the hearing device housing 1, processes the microphone signals and amplifies them. The output signal of the signal processing unit 3 is transmitted to a loudspeaker or earpiece 4 which outputs the acoustic signal. The sound is transmitted, if necessary via a sound tube which is fixed with an otoplastic in the auditory canal, to the hearing device wearer's eardrum. The power is supplied to the hearing device and especially to the signal processing unit 3 by a battery 5 also integrated into the hearing device housing 1.